Feeder

ABSTRACT

A feeder operable to convey a divided solids material comprises a conduit and an actuator. The conduit has a hollow body with a length, a first end, a second end opposite the first end and a displaceable body segment defined along at least a portion of the length. The displaceable body segment has at least a first fixable location positionable at a first fixed location. The actuator is positioned to apply force to the conduit and is controllable to cause selected flow of divided solids material in a feed direction extending generally from the first end to the second end. Methods are also disclosed.

BACKGROUND

Silicon of ultra-high purity is used extensively in the electronics andphotovoltaic industries. High purity granular polysilicon materials withonly trace of amounts of contamination measured at the part per billionlevels are often required. Producing such materials is possible, butthen extreme care must be taken in any handling, packaging ortransportation operations to avoid subsequent contamination.

Conventional feeding and flow control technologies used to conveygranular polysilicon materials includes components having metal in theirconstruction (e.g., valves, conduits, etc.). When protective coatings orlinings are compromised, or when wear occurs at the interfaces of movingparts, for example, contamination from metal parts can occur, which isunacceptable.

Valves used to regulate the flow of granular materials that rely oncomponents that move relative to the material being conveyed, such asbutterfly dampers, pinch bladders, diaphragms, gates, etc., have adisadvantage of potentially crushing granules of the material, which canboth reduce its value and potentially damage the components and otherequipment.

In addition, conventional feeders may not provide sufficient controlover the rate of flow granular polysilicon and/or the flow rate range.Conventional vibrating tray feeders may achieve a feed rate rangebetween a lowest controllable feed rate and a highest controllable feedrate of only about 1:50, but a much higher feed rate range is desirable.Other conventional approaches allow higher feed rate ranges to beachieved, but only with apparatus having multiple parts within thecontrol volume of the flowing material that must move relative to eachother, such as auger screws, rotary vanes and other similar structures.Multiple parts in relative motion within the control volume, however,leads to a greater risk of contamination.

Also, such conventional feeders are difficult to purge with a suitableprocess gas and/or clean in part because of their complicatedconstructions. The multi-piece constructions typically require anextensive use of seals to prevent leakage through components that moverelative to each other.

Conventional vibratory solids conveyors typically have a rigid containerconstrained by linkages and/or springs that can be driven by aneccentric weight assembly coupled to an electric motor or anelectromagnetic drive in a desired motion, such as elliptical rotationthat includes horizontal and vertical components.

Conventional approaches to conveying solids, including vibratoryconveyors, screw augers, belt conveyors and other similar devices, arenot capable of achieving high performance over a large range of flowswhile ensuring that ultrahigh purity is maintained.

SUMMARY

Described below are apparatus and methods that address some of thedrawbacks in conventional approaches to feeding solids materials,including granular polysilicon.

According to a first implementation, a feeder operable to convey adivided solids material comprises a conduit and an actuator. The conduithas a hollow body with a length, a first end, a second end opposite thefirst end and a displaceable body segment defined along at least aportion of the length. The displaceable body segment has at least afirst fixable location positionable at a first fixed location. Theactuator is positioned to apply force to the conduit and controllable tocause selected flow of divided solids material in a feed directionextending generally from the first end to the second end.

In some implementations, the actuator is supported by the conduit andmoves with the displaceable body segment during a feeding operation. Theactuator can comprise a rotating offset mass, and the rotating offsetmass can be operated to generate oscillating motion of the displaceablebody segment and the attached actuator. The displaceable body segmentcan be cyclically displaced through a closed trajectory having at leastone of a vertical component and a horizontal component.

In some implementations, the displaceable body segment has a secondfixable location downstream of the first fixable location in the feedingdirection and positionable at a second fixed location.

In some implementations, the displaceable body segment has a curvedprofile with a length longer than a shortest distance separating thefirst fixable location and the second end, and the actuator is attachedto the displaceable body segment approximately at an inflection pointfor a curve of the curved profile.

In some implementations, the actuator is positioned stationarily and hasa controllably movable element that contacts the displaceable bodysegment. In some implementations, the actuator comprises a linearactuator. In some implementations, the actuator comprises an elongatemember having a distal end pivotable into contact with the displaceablebody segment to selectively move the displaceable body segment and aproximal end pivotably connected to a pivot point.

In some implementations, the displaceable body segment comprises anintermediate section configured to collect a portion of the dividedsolids material when the displaceable body segment is at rest. Theintermediate section can be configured to collect a leading edge of aflow of divided solids material received from the first end of thefeeder.

In some implementations, the intermediate section is configured forpositioning at a slight angle relative to horizontal, and there is afirst upright section positioned upstream of the intermediate sectionand a second upright section positioned downstream of the intermediatesection.

In some implementations, the conduit is made from a resilient material.In some implementations, the conduit comprises polyurethane hosematerial.

In some implementations, a feeder comprises a conduit and an actuator.The conduit has an inlet end, an outlet end opposite the inlet end and adisplaceable body segment along a feeding direction between the inletend and the outlet end. The inlet end is configured for connection to asource of material to be fed by the feeder. The outlet end is configuredto convey divided solids material from the feeder to a locationdownstream of the feeder. The outlet end is positioning at a lowerheight than the inlet end. The displaceable body segment is sized tohave a length longer than a shortest distance between the inlet end andthe outlet end and to define a curved profile with at least oneinflection point when installed. When installed, the displaceable bodysegment defines an intermediate section configured to supportaccumulated material therein at an angle of repose of the material, andto reduce movement of material in the feeding direction when thedisplaceable body segment is at rest. The actuator is connected to thedisplaceable body segment to controllably displace the displaceable bodysegment in a feeding operation.

In some implementations, the actuator is controllable to displace thedisplaceable body segment in an oscillating cycle. In someimplementations, the actuator is manually operable. In someimplementations, the displaceable body segment extends substantiallyfrom the inlet end and substantially to the outlet end.

In some implementations, the intermediate section is caused to bedisplaced from a substantially lateral position at which no flow occursto a downwardly tilted position at which flow towards the outlet endoccurs.

In some implementations, the actuator can be configured to move at arate sufficient to cause displacement of the displaceable body sectionsuch that the solids material moves at a selected rate between a lowtrickle flow and a high bulk filling flow.

According to a method implementation, a method of conveying a dividedsolids material with a feeder comprises using a sensor to monitor anamount of the divided solids material being conveyed with the feeder,receiving signals from the sensor at a controller and sending controlsignals from the controller to the feeder to control a flow rate of thedivided solids material over a flow rate range ratio of greater than1:50 of a low flow rate to a high flow rate.

According to some implementations, using a sensor to monitor an amountof the solid material being conveyed can comprise configuring the sensorto measure a loss of weight of the solid material from a source of thematerial positioned upstream of the feeder. According to someimplementations, using a sensor to monitor an amount of the solidmaterial being conveyed comprises configuring the sensor to measure again in weight from the solid material conveyed to a receptaclepositioned downstream of the feeder.

According to some implementations, the feeder can comprise a conduitsegment for receiving the solid material and that is displaceableaccording to the control signals from the controller to achieve adesired flow rate of the material from the feeder. In someimplementations, the flow rate range ratio is greater than 1:4000.

According to another method implementation, a method of conveyingdivided polysilicon comprises receiving divided polysilicon from asource into a conduit of a feeder, controllably moving the conduitthrough an operation path in which the conduit is positioned in at leasta first position at which flow through the conduit occurs and a secondposition at which flow through the conduit is stopped, and receiving thedivided silicon material flowing through the conduit, when the conduitis positioned at least in a first position, in a receptacle positioneddownstream of an outlet end of the conduit.

Desirably, the feeding and flow control technologies described hereintend not to rely on reducing the cross section of the conduit, whichreduces damage to the material being conveyed and the equipment.

The foregoing and other objects, features, and advantages will becomemore apparent from the following detailed description, which proceedswith reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is side elevation view of a representative implementation of afeeder in its at rest position.

FIGS. 2-13 are side elevation views of the feeder of FIG. 1schematically showing the feeder of FIG. 1 and material being fed withthe feeder in different positions throughout several cycles of motion.

FIG. 14 is a graph showing the trajectory of the motor and a segment ofthe body of the feeder through a cycle with reference to the positionsshown in FIGS. 2-13.

FIG. 15 is a graph of feed rate for the feeder vs motor speed.

FIG. 16 is a table of data used to plot the graph of FIG. 15.

FIGS. 17-18 are side elevation views of another implementation of thefeeder in which the actuator for moving the body is a double actingpneumatic cylinder.

FIG. 19 is a schematic block diagram of a representative control circuitfor regulating operation of the feeder as a gravimetric feeder accordingto control based on a loss of weight.

FIG. 20 is a schematic block diagram of a representative control circuitfor regulating operation of the feeder as a gravimetric feeder accordingto control based on a gain in weight.

FIG. 21 is a schematic block diagram of a representative control circuitfor regulating operation of the feeder as a volumetric feeder.

FIG. 22 is a side elevation view of another implementation of the feederin which a vacuum or suction device has been added to assist incontrolling dust during feeding operations.

FIG. 23A is a side elevation view of another implementation of thefeeder in which an intermediate section is constrained to control flowas desired.

FIG. 23B is an enlarged section view of a portion of the feeder of FIG.23A showing solids in the feeder at rest when the feeder is in a zeroflow position.

FIG. 24A is a side elevation view of the feeder of FIG. 23A showing thefeeder in a different position.

FIG. 24B is an enlarged section view of a portion of the feeder of FIG.24A showing solids in the feeder beginning to flow.

FIG. 25A is a side elevation view of the feeder of FIG. 23A showing thefeeder in another different position.

FIG. 25B is an enlarged section view of a portion of the feeder of FIG.25B showing solids in the feeder and the feeder positioned for maximumflow.

FIGS. 26A and 26B are side elevation views showing variations of thefeeder of FIG. 23A having members of different lengths.

FIGS. 27A and 27B are side elevation views of the feeder of FIG. 23Ashowing another variation in the member.

DETAILED DESCRIPTION

Referring to FIG. 1, a side elevation view of a representativeimplementation of a feeder 100 through which material can be fed isshown. The feeder 100 has a body 102 that is generally tubular, which isalso sometimes referred to herein as a conduit. Because the body 102 istubular, it has a hollow cross section. The cross section of the body102 may define an inner surface that is circular, elliptical, rounded oreven multi-sided. The outer surface may have any suitable shape, and thewall(s) between the inner surface and outer surface may have anysuitable thickness (constant or variable).

The body 102 has a first end 104 and an opposite second end 106. Betweenthe first and second ends 104, 106, there is a displaceable body segment108 that can be caused to displace or move, or to vibrate or oscillate(and in some cases, to do so cyclically), as described below in greaterdetail, to cause material to be conveyed or fed from the first end 104,through the body 102 and to the second end 106. The body 102 is formedof one or more materials and to have selected dimensions such that itcan be moved between different positions as desired, which is describedbelow in more detail.

In some implementations, the material to be fed or conveyed is one ormore solids materials comprising particles, such as a divided solidsmaterial. Polysilicon is one example of a material that can be providedas a divided solids or finely divided solids material. Other materialscan also be fed using the described apparatus and methods. Also, thematerial to be fed can be a mixture of two or more different componentmaterials.

A material is defined to be flowable if the bulk stress acting on thematerial exceeds the material's bulk strength. In the case of a granularmaterial, one measurement used to indicate a material's ability to flowis the angle of repose of the material. The angle of repose of agranular material is the steepest angle of descent or dip relative tothe horizontal plane to which the material can be piled without slumping(at this angle, the material on the slope face is on the verge ofsliding). A material that has a lower tendency to flow may be comprisedof particles with a relatively high degree of inter-particle friction,such as particles of a material having more angular shapes that tend tointerlock with each other. In the same way, flowability of a materialtends to be decreased if there is plastic deformation of particles,partial melting of particles, moisture present in and/or aroundparticles and/or another factor tending to increase adhesion betweenparticles.

In some cases, when particles of a material are at rest and not flowing,e.g., because the angle of repose for the material has not beenexceeded, the particles can nevertheless be induced to flow bydisturbing them, such as through applying energy to them, e.g., in theform of vibrations.

In the case of granular polysilicon (also sometimes referred to hereinas granulate polysilicon and granules), the polysilicon particles aregenerally spheroids having an average diameter of 0.25 to 20 mm, such asan average diameter of 0.25-10 mm, 0.25-5 mm, or 0.25 to 3.5 mm. As usedherein, “average diameter” means the mathematical average diameter of aplurality of granules. Individual granules may have a diameter rangingfrom 0.1-30 mm, such as 0.1-20 mm, 0.1-10 mm, 0.1-5 mm, 0.1-3 mm or0.2-4 mm. The individual particles of any given material may havegenerally the same size and shape, or they vary in size and shape.

The open cross section of the tubular body 102 or conduit can sized tobe at least 2-3 times greater than the major dimension of the largesttarget particle size such that flow of particles of such size throughthe feeder is facilitated. In specific examples, the major dimension isa diameter that is 2-3 times, 5 times, 10 times or 100 times thediameter of the largest target particle size of the material to beconveyed.

The first end 104 can be connected to an upstream source of material tobe fed, such as a material comprising solids. In the illustratedimplementation, the first end 104 is connected to the outlet end of ahopper H, which is stationary. Instead of the hopper H, the feeder 100can be connected downstream of any other component or conduit thatsupplies material to be fed. The second end 106 can be connected to anoutlet from which material fed by the feeder 100 is discharged as shown,or to any other downstream location. As shown in FIG. 13, for example,the second end 106 can convey material to a receptacle R.

The displaceable body segment 108 can have a first fixable location 110,e.g., a location that is positionable at a first fixed location.Similarly, the displaceable body segment 108 can have a second fixablelocation 112, e.g., a second location that is fixable at a second fixedlocation. The first and second fixable locations 110, 112 define theapproximate ends of the displaceable body segment 108. In theillustrated implementation, the first fixable location 110 is located inthe area of the first end 104, and second fixable location 112 islocated in the area of the second end 106. In other implementations, thefirst and second fixable locations 110, 112 can be located at pointsspaced from the first and second ends 104, 106, respectively, to definedisplaceable body segments of different lengths and characteristics.

Typically, at least the displaceable body segment 108 is configured tobe sufficiently flexible to be displaced as desired, such as byselecting appropriate material(s) and their dimensions. As one example,in the illustrated implementation, the body 102, including thedisplaceable body segment 108, is formed of a section of flexiblepolyurethane hose or conduit having an appropriate uniform diameter andwall thickness. In other implementations, one or more differentmaterials may be used for the body 102 and/or displaceable body segment108, and/or non-uniform wall thicknesses and/or diameters may be used.

As shown in the implementation of FIG. 1, there are no moving partswithin the displaceable body segment 108, i.e., there are no movingparts within the internal volume defined by the displaceable bodysegment 108, which can be designated as part of the control volume forthe feeder. This is advantageous because contact between solid materialflowing through the displaceable body segment 108 and any moving partsor other sensitive areas causes wear and other problems, particularlywith solid material such as granular polysilicon.

As also shown in FIG. 1, the feeder 100 has an actuator, e.g., a motor130 or other device configured to move the body 102, and in particularthe displaceable body segment 108, to cause it to selectively oscillateor otherwise move, typically in a cyclical fashion. The motor 130 ispositioned to impart motion to the displaceable segment 108, such as bybeing mounted to the body 102 as shown (or having a component thatcontacts the body). The motor 130 can be an electric motor having aneccentric weight. As stated, any other type of actuator or other devicesufficient to impart the desired motion to the displaceable body segment108 could also be used, such as a pneumatic cylinder, a hydrauliccylinder, or a mechanical drive such as a rack and pinion assemblypowered by a servo motor, as a few examples.

Referring to FIG. 1, the body 102 has an S-shaped profile in elevation.In the vertical direction, the first end 104 is positioned at a levelabove the second end 106. In the horizontal direction, the first andsecond ends 104, 106 are offset from each other. The S-shaped profile ofthe body 102 has two curves bending in opposite directions in a singleplane that meet at inflection point within the displaceable body segment108. Other configurations can also be used, depending on the particularoperating requirements for the application. In the illustratedimplementation, the motor 130 is positioned to have its rotational axissubstantially perpendicular to the displaceable body segment 108.

Referring again to FIG. 1, the body 102 is shown as a transparentcomponent to allow its interior and the material M to be illustrated.The feeder 100 is shown partially filled with material M that has cometo rest at an intermediate point within the body 102. A leading edge orhead portion of the material M, which is inclined from left to right inFIG. 1, in inclined at the material's angle of repose A. In theillustrated implementation, e.g., the angle of repose for the materialM, such as granular polysilicon material, is approximate 31°. Thesection of the body 102 in FIG. 1 where the material M is at rest can bedescribed as an intermediate section (also sometimes referred to as arepose section). The intermediate section can be approximately level inthe downstream direction as shown (i.e., from right to left in FIG. 1),angled upwardly or angled downwardly, together with any necessary changeto the section's length to ensure that sufficient run out is provided,to assist in ensuring that no flow occurs when the feeder 100 is notoperating. The segments adjacent the first and second ends 104, 106 canbe relatively upright as shown to have the material flowing into and outof the body 102 assisted by gravity to a maximum degree, but otherconfigurations are also possible.

By displacing or moving the displaceable body segment 108 as describedin more detail below, the material M can be moved or feed through thebody 102 along a feed path as indicated generally by the arrows F (see,e.g., FIGS. 2, 5, 6, 9-13) and out through the second end 106 to asubsequent component and/or location.

The steady state cyclical motion of the feeder 100 in a representativeoperating scenario is shown in FIGS. 2-13. Specifically, FIGS. 2-13 areadditional side elevation views of the feeder 100 showing how operationof the motor 130 causes oscillatory motion of the displaceable bodysegment 108. Referring to FIG. 2, during steady state operation of themotor 130 at a speed of 225 RPM in the counterclockwise direction, theposition of the motor 130 has moved to the right and down. Specifically,at a time of 0.07 seconds relative to an arbitrary starting point on themotor's steady state trajectory, the motor 130 has moved 2.7 cm to theright (Delta X=+2.7 cm) and 2.3 cm down (Delta Y=−2.3 cm). Because themotor 130 is attached to the displaceable body segment 108, thedisplaceable body segment has substantially the same motion as the motor130.

As the displaceable body segment 108 moves down to the right, thematerial M, and specifically, the granules that make up the material M,have a relative velocity that is in a direction up to the left, therebycreating a void V in the material M as shown schematically in FIG. 2.The growing void V is not constrained by the material's angle of repose,and so material will begin to flow from right to left, beginning in theintermediate section along the flow path F. As flow of materialcontinues, the void V will be filled, and additional material from thehopper H will enter the body 102 to replace the material flowing awayfrom the intermediate section. It can be said that the material beingfed is entrained in pockets and sequentially moved throughout thefeeding process. A profile or trajectory P of the cyclical motion of themotor 130/displaceable body segment 108, which is described below ingreater detail in connection with FIG. 14, is shown superimposed on therotational axis of motor 130 in FIGS. 2-13.

Subsequently, as shown in FIG. 3, while the motor speed is maintained at225 RPM and at 0.14 seconds, the displaceable body segment 108 and thematerial M are accelerated up to the left. The void V is collapsed, andthe material M is once again constrained by its angle of repose, but atposition farther along the flow path F. Flow from the hopper H isstopped. At the point shown in FIG. 3, the motor 130/displaceable bodysegment 108 have moved 4.5 cm to the left (Delta X=−4.5 centimeters),and 2.4 cm up (Delta Y=2.4 cm) from the position shown in FIG. 2.

In FIG. 4, at 0.20 seconds, the displaceable body segment 108 reachesits left most position, stops and starts to move down to the rightagain. The material M maintains its velocity in a direction up to theleft. Relative flow between the hopper H and body 102 remains stopped.At this point, Delta X=−2.3 cm and Delta Y=1.8 cm relative to theposition shown in FIG. 3.

In FIG. 5, at 0.27 seconds, the inertia of the material M causescontinued motion up to the left with the displaceable body segment 108moving down to the right. At this point, the relative velocity is at itsmaximum. The flow at the head portion of the material along with thedisplaceable body segment 108 moving down to the right produces a morerapidly growing void V. Because the material M is not constrained by itsangle of repose, flow of material starts to fill the void V. Flow fromthe hopper H resumes to replace material flowing below. At this point,Delta X=4.2 cm and Delta Y=−1.8 cm relative to the position shown inFIG. 4.

In FIG. 6, at 0.34 seconds, the inertia of the material M allowscontinued motion up to the left at the head portion of the material.With the material continuing to flow, along with movement of thedisplaceable body segment 108 down to the right, voiding continues totake place. Because the material is not constrained by its angle ofrepose, flow continues to fill the void. Flow from the hopper Hcontinues to replace material flowing below. At this point, Delta X=2.7cm and Delta Y=−2.3 cm relative to the position shown in FIG. 5.

In FIG. 7, at 0.41 seconds, the head of the material M can be seenadvancing along the flow path F. The displaceable body segment 108 andmaterial M are accelerated up to the left. The void V has collapsed, andgranular material is once again constrained by its angle of repose.Relative flow between this granular material and the downstream sectionof the displaceable body segment 108 has stopped. Flow from the hopper Hhas stopped. At this point, Delta X=−4.5 cm and Delta Y=2.4 cm relativeto the position shown in FIG. 6.

In FIG. 8, at 0.47 seconds, the material M is advancing farther alongthe flow path F. The displaceable body segment 108 has reached its upperleft most position. It will then stop, and start to move down to theright. The inertia of the material M remains in a direction up to theleft. Relative flow in the downstream direction in the displaceable bodysegment 108 has stopped. Flow from the hopper H has stopped. At thispoint, Delta X=−2.3 cm and Delta Y=1.8 cm relative to the position shownin FIG. 7.

In FIG. 9, at 0.54 seconds, the displaceable body segment 108 is movingdown to the right and has reached its maximum velocity. The flow in thedisplaceable body segment 108 produces a more rapidly growing void V.Because the material is not constrained by its angle of repose, materialstarts to fill the void. Flow from the hopper H resumes to replacematerial flowing below. At this point, Delta X=4.2 cm and Delta Y=−1.8cm relative to the position shown in FIG. 8, i.e., the same position asis shown in FIG. 5. Thus, one cycle is depicted in the sequence fromFIG. 5 through FIG. 9.

In FIG. 10, at 0.61 seconds, the inertia of the material M allowscontinued motion up to the left along the displaceable body segment 108and into a discharge segment of the body 102. The discharge segment canbe positioned substantially upright as shown. With the materialcontinuing to flow along the flow path, along with movement of thedisplaceable body segment down to the right, voiding continues to takeplace. Because material is not constrained by its angle of repose, flowcontinues to fill the void. Flow from the hopper H continues to replacematerial flowing below. At this point, Delta X=2.7 cm and Delta Y=−2.3cm relative to the position shown in FIG. 9.

In FIG. 11, 0.68 seconds, the head portion of the flow of material alongthe flow path begins to fall from above through the discharge sectiontoward the second end 106. Material is also advancing elsewhere alongthe flow path. The displaceable body segment 108 and the material M areaccelerated up to the left. The void has collapsed, and material is onceagain constrained by it angle of repose. Flow between the intermediatesection and points downstream has stopped. Also, flow from the hopper Hhas stopped. At this point, Delta X=−4.5 cm and Delta Y=2.4 cm relativeto the position shown in FIG. 10.

In FIG. 12, at 0.74 seconds, material at the head portion of the flowcontinues to fall toward the end 106. Material is also advancing throughintermediate points along the flow path. The displaceable body segment108 has reached the upper left most position, stopped and started tomove down to the right again. The material M has maintained its velocityup to the left. Flow between the angle of intermediate section anddownstream segments has stopped. Flow from the hopper has stopped. Atthis point, Delta X=−2.3 cm and Delta Y=1.8 cm relative to the positionshown in FIG. 11.

In FIG. 13, at 0.81 seconds, material at the head portion of the flow,continues to fall as accelerated by gravity through the second end 106and is discharged from the feeder 100. Material is advancing through thedisplaceable body segment 108 with the displaceable body segment 108moving down to the right. The relative velocity of the displaceable bodysegment 108 is at its maximum. The flow in the intermediate sectioncauses a void V to grow. Because the material is not constrained by itsangle of repose, flow starts to fill the void. Flow from the hopper Hresumes to replace material flowing below. At this point, Delta X=4.2 cmand Delta Y=−1.8 cm relative to the position shown in FIG. 12.

As described above, FIG. 14 is a graph of X axis and Y axis motion ofthe motor 130 and the displaceable body segment 108 showing theirtrajectory P and including references to show how the positions of FIGS.2-13 correlate to points on the trajectory. Although FIGS. 2-13 showspecific times for convenience of illustration, the motion throughoutthe cycle continues smoothly between discrete points as indicated by thetrajectory P. Although not specifically shown in the figures, therewould typically be a smooth ramping up of speed to the desired operatingspeed (e.g., 225 rpm).

By maintaining the motion of the displaceable body segment 108predominately in the XY plane, feeding efficiency is maximized, andpotential drawbacks from motion with components in the Z direction(i.e., perpendicular to the page), which could introduce torsionalvibrations adverse to feeding, can be avoided. Thus, the motor 130 (aswell as the cylinder 230 described below) can be positioned such thatthe forces they produce act predominately in the XY plane. For the motor130, the mounting can also be configured so that the swinging mass doesnot introduce torsional vibration effects that would tend to counteractsmooth feeding.

As described, the motion of the displaceable body segment 108, and theresulting performance of the feeder, is influenced by a number ofvariables. One such variable is the direction in which the motor isrotated relative to the shape or profile of the displaceable bodysection 108, including whether the motor's rotation tends constrict orrelax the curved sections in the displaceable body segment 108. Anothervariable concerns the magnitude and direction of residual forces in thedisplaceable body segment 108 tending to resist the action of the motor(e.g., due to the stiffness of the hose material and/or itsconfiguration). Depending upon the particular needs for a specificsituation, the user may determine that one direction of rotation ispreferred over the other and/or that the displaceable body segmentshould be configured to have selected characteristics.

FIG. 15 is a graph showing how feed rate through the feeder 100 for thematerial (in g/second, and plotted on a logarithmic scale) increases asthe rotational speed of the motor 130 (in Hz) is increased. FIG. 16 is atable providing data points for the graph of FIG. 15. Overall, thefeeder 100 shows excellent results with a predictably increasing feedrate as motor speed is increased, and a wide usable range. Repeatedtests have shown that these results are reproducible and accurate.

At high speeds, the eccentric weight of the motor 130 provides both ahigh centrifugal force and a high frequency to produce a high feed rate.Conversely, at low speeds, the eccentric weight provides a lowcentrifugal force amplitude at a low frequency. The motion of arepresentative feeder was studied using video analysis. Feed rate datacorresponding to the video analysis was obtained by evaluating a massvs. time relationship of the feeder's discharge. The mass of thematerial collected from the discharge was weighed in a containersupported by a load cell (such as, e.g., a Model RAP3 single point loadcell provided by Loadstar Sensors of Fremont, Calif.). Comparisons ofthis measured feed rate data with a calculated feed rate based onmodelling the feeder as a positive displacement pump show excellentagreement.

By way of contrast to conventional vibratory feeders, the feeder 100operates in a different frequency-amplitude regime. Referring again toFIG. 16, the feeder in a representative embodiment operates over afrequency range of 1.08-3.75 Hz and has a maximum amplitude of about 80mm (at 100% speed, with the intermediate section at an average inclineof about 30 degrees from horizontal). In contrast, a conventionalelectromagnetic driven rigid tray feeder operates over a frequency rangeof 20-60 Hz and an amplitude of 1-11 mm. Similarly, a conventionaleccentric motor driven rigid tray feeder operates over a frequency rangeof 15-30 Hz and an amplitude of 1-10 mm. Likewise, another conventionalmechanically driven rigid tray feeder operates over a frequency range of5-15 Hz and an amplitude of 3-15 mm. Thus, the feeder operates over amuch lower frequency range and reaches a much greater amplitude.

The electric motor 130 may be configured to be controlled by a variablefrequency drive (VFD), either as a separate component or providedintegrally with the motor. Such a VFD-controlled motor provides precisecontrol over the speed of the motor, and thus allows a desired flow rateto be achieved. As a result of the frequency-amplitude control of thefeeder, the feeder is capable of a flow rate range of 1:4700, which isfar greater than the flow rate range of about 1:50 achievable with aconventional vibrating tray feeder.

Because the feeder 100 can achieve flow rates ranging from a trickleflow at very low motor speeds to very high flow rates at high motorspeeds, it can be operated in a variety of different ways, whichincreases the flexibility of its use. As one example, in operating thefeeder to reach a target weight of material to be output, the feeder canbe operated at high speed for an initial period and then at low speedfor a subsequent period as the target weight is approached. Thus, thefeeder is very well suited for use in a continuous process where flowcontrol of material is required. The feeder can be used as a gravimetricfeeder in bulk filling applications.

FIG. 19 is a schematic block diagram of a control system for the feeder100 configured as a gravimetric feeder. In gravimetric feeding, materialis fed into a process at a constant weight per unit of time since weightis a variable that can be readily captured by a weighing module.According to the loss in weight type of gravimetric feeding of FIG. 19,the amount of material fed into the process is weighed at a source ofthe material. Thus, there is a source load cell 310 coupled to acontainer representing the source of material (not shown, but generallylocated upstream of the feeder 100) that is connected to a controller320 to send signals corresponding to the container's loss in mass duringa feeding operation. The controller 320 is connected to the feederactuator (i.e., the motor 130) or other moving mechanism to send controlsignals to carry out controlled operation of the feeder 100 in reachinga desired target, e.g., conveying a desired mass of the material,including through control of the flow rate of material. Additionalfeedback control could also be used.

As also shown in FIG. 19, an optional logic circuit 330 with a containersensor 332 and a container sensor circuit 334 can be provided. Ifprovided, the container sensor 332 can be configured to monitor whethera receiving container, such as the receptacle R in FIG. 13, is in place.The container sensor circuit 334 can be configured to send a signal tothe controller 320 to indicate that a receiving container is in place(container ready=Y) and that a feeding operation can be commenced.

FIG. 20 is similar to FIG. 19, but shows a schematic block diagram forthe feeder 100 configured as a gain in weight type gravimetric feeder.According to the gain in weight type of gravimetric feeding of FIG. 20,the amount of material fed into a process is weighed at a receivingcontainer. Thus, there is a load cell or other equivalent sensor 312coupled to the receiving container (such as the receptacle R). Thesensor 312 is connected to the controller 320 to send signals indicatingthe receiving container's gain in mass during a feeding operation. Asabove, the controller 320 carries out a feeding algorithm and sendscontrol signals to the motor 130 or other mechanism. Also, the optionallogic circuit 330 can be implemented, if desired.

FIG. 21 is similar to FIGS. 19 and 20, but shows a schematic blockdiagram for the feeder 100 configured as a volumetric feeder instead ofa gravimetric feeder. As indicated, the controller 320 is connected tosend control signals to the motor 130 based on a control algorithm basedon stored data 322, such as speed (cycle) volumetric flow datadescribing a relationship between operating speed of the motor and flowrate. Also, the optional logic circuit 330 can be implemented, ifdesired.

Another implementation of the feeder can be described in connection withFIGS. 23A-25B. Referring first to FIG. 23A, a feeder 400 has the firstend 104 of the body 102 at a first fixed location 110 similar to thefeeder 100, but has an elongate member 420 proximate to at least asegment of the body 102, generally between its ends 104, 106. The member420 is operable to apply a force and/or torque to the segment of thebody 102 (and thus can be described as another form of “actuator”), aswell as to constrain the body 102 to move on a selected path. In mostcases, the force and/or torque produces at least some displacement inthe body 102 along all points that are not fixed. Thus, the displaceablebody segment 108 of the body 102 in the feeder 400 can be defined asextending from close to the first end 104 to close to the second end 106(if fixed) or to the second end (if free to move). In certainimplementations, there could be multiple displaceable body segments.

The member 420 has a distal end 421 that is configured to contact thebody 102 within the displaceable body segment 108, and an oppositeproximal end 423. The proximal end 423 of the member 420 is pivotablysupported to pivot about a pivot point 414. As is described below inmore detail, it is only the member 420 that is connected at the pivotpoint 414, and not any part of the body 102. Rather, the displaceablebody segment 108 of the body 102 is contacted by the distal end 421 ofthe member 420. In the illustrated implementation, the displaceable bodysegment 108 is contacted by a band clamp 422 that at least partiallyencircles it and extends lengthwise from the distal end 421 proximallyover a length of the band clamp 422.

By moving the member 420, e.g., by pivoting the member 420 about thepivot point 414, the displaceable body segment 108 is moved and morespecifically, an intermediate section I thereof can be rotated to aselected angle, such as to shut off feeding (zero feed rate), to allowfor feeding at a maximum rate and/or to allow for feeding at ratesbetween the zero feed rate and the maximum feed rate. In someimplementations, the member 420 extends along the displaceable bodysegment over at least a portion of the length of the member 420.

The pivoting operation can be accomplished in discrete operations or asin cyclical operations. Further, the rotation of the intermediatesection I can be accomplished manually or as step in an automaticfeeding process. In the illustrated implementation, the member 420 has aforked end (not shown) that straddles the body 102 and is pivotablysupported at the pivot point 414.

The intermediate section I (which tends to move greater distances thatother sections of the displaceable body segment 108 during operation) isshown schematically in FIG. 23A to include the section contacted by theband clamp 422, and adjacent sections upstream and downstream thereof.Depending upon a variety of factors, almost any point along the body 102except the first end 104 (which is fixed) may undergo at least a smalldisplacement during pivoting and thus is considered part of thedisplaceable body segment 108.

The geometry of the intermediate section I, including its slope, theradii of its bends and inflection point, are selectively controlled by anumber of factors, including the length and path of the body102/displaceable body segment 108, the location of the pivot point 414(i.e., the vertical distance of the pivot point 414 below and thehorizontal distance offset from the first end 104), the geometry of themember 420, the angle of rotation of the member 420 and the flexuralproperties of the body 102. For a displaceable body segment 108 formedof a length of hose, the flexural properties of the body account for thetype of hose, the thickness of the hose material and other similarproperties. Desirably, moving the member 420 to cause the intermediatesection I to rotate as described does not collapse displaceable bodysegment 108 or otherwise interfere with feeding taking place within itexcept as intended.

In the feeder 400, the second end 106 of the body 102 can be fixed ormovable. If the second end 106 is fixed, it may be relatively aligned inthe vertical direction with the first end 104 as shown in FIG. 23A, orit may be horizontally offset from the first end 104.

The member 420 can be described as defining an offset radius (or pivotlength) between the point at which it acts on the displaceable bodysegment 108 (i.e., at the member/body interface, which is at thelocation of the band clamp 422 in the illustrated implementation) andthe pivot point 414. FIG. 26A is an enlarged side elevation view showinga member 420 having approximately the same offset radius as in FIG. 23A.FIG. 26B is an enlarged side elevation view showing a member 420defining a shorter offset radius.

Overall, the geometry of the member 420 and the location of the pivotpoint 414 are influenced by the design envelope of the feeder 400. Asshown in FIGS. 23A and 23B, a design goal of the feeder 400 is toprovide a minimum height difference between the first end 104 and pointat which the member 420 contacts the displaceable body segment 108(i.e., the member/body interface, which is at the location of the bandclamp 422 in the illustrated implementation) to achieve a compactconfiguration, while at the same time allowing the displaceable bodysegment 108 to achieve the necessary geometries for both the shut offand maximum flow positions. To accommodate the change between thesegeometries while respecting the constraints of the body 102/displaceablebody segment 108, such as conservation of length (not requiring the hoseto stretch or compress) and minimum bend radius (not requiring the hoseto bend too tightly as to risk kinking it), and to reduce the amount ofstress on the body, the resulting positions of the member/body interface(band clamp 422) can be varied in both height and horizontal location.To work within the constraints of the displaceable body segment 108while permitting the second end 106 to move, a convenient method ofmoving the member/body interface (band clamp 422) along an arc toachieve precise shutoff, intermediate, and maximum flow geometriesinfluenced the selected geometry of the member 420.

Given a larger allowed envelope in which to provide flexing of the body102 between at least the first fixed end 104 and the member/bodyinterface (as well as between the member/body interface and anydownstream fixed point, such as a fixed second send 106, if present),the length of the body 102/displaceable body segment 108 could beextended, permitting the member/body interface (band clamp 422) to bepositioned to coincide with the pivot point 422. In this case, themember 420 is configured to rotate about itself without changing inheight or horizontal position (i.e., a zero radius offset), while at thesame time keeping stresses experienced in the body within acceptablelevels. For example, as shown in FIG. 27A, the member/body interface(band clamp 422) of the member 420 is positioned to coincide with thepivot point 414. FIG. 27B is similar to FIG. 27A, and showsschematically how the geometry of the displaceable body segment ischanged by rotating of the member 420 acting on the body through themember/body interface (band clamp 422) at the pivot point 414.

Instead of the member 420, other arrangements can be used. For example,an actuator similar to the actuator 230 could be configured to move thedisplaceable body segment 108. Other approaches to generating anappropriate torque and/or force applied at a suitable location(s) arealso possible. As another example, it is also possible to have the forceor torque applied very close to or at the pivot point 414.

In one operation mode, the member 420 is moved manually to change theangle of the intermediate section I of the body 108. FIG. 23B is anenlarged sectioned depiction of a portion of the body 108 of the feeder400 of FIG. 23A, including the intermediate section I, that is shownschematically to be filled with granular material M, such as granularsilicon. (The member 420 has been excluded from FIG. 23B for clarity.)

As illustrated in FIG. 23B, the granular material M is not flowingbecause it is constrained at the limit of its angle of repose (in thecase of granular silicon, the characteristic angle of repose is) 31°.Thus, the gravitational force that would tend to cause the granularsilicon to flow farther through the body is balanced by the material'stendency to accumulate at its angle of repose, so the material M remainsstationary. The dashed line illustrates schematically that the angle ofrepose for a leading edge of the material M intersects with a lower sideof the hose, so no flow is possible. The position illustrated in FIGS.23A and 23B is referred to as the shutoff position. In the specificexample of FIG. 23A, with a hose having a diameter of 1.5 inches andbeing positioned as shown, and the member 420 being configured as shown,the member 420 was moved to a position 8° below horizontal to achievethe precise shutoff position shown in FIG. 23B.

In FIGS. 24A and 24B, the positioning of the body 108 to achieve aminimum flow condition is shown. By moving the member 420 to a position13.6° below horizontal, the leading edge of the accumulated material Min the intermediate section shown by the dashed line now extends beyonda drop-off point and within an open area of the body 108, and so thematerial M just begins to flow.

In FIGS. 25A and 25B, the body 108 has been positioned as shown toachieve a maximum flow condition. By moving the member 420 to an angleof 29.7° below horizontal, maximum flow is achieved. It was observedthat greater angles below horizontal (i.e., making the hose morevertical) did not achieve a higher flow rate because of limitingupstream flow resistance (flow friction and/or pressure balance).

In the representative implementation of FIGS. 23A-25B, it was possibleto achieve highly controllable flow rates for granular silicon materialacross a range from 11 grams per second to 740 grams per second.Further, the flow rates were consistent as a function of time.

As stated, the feeder 400 can be implemented for manual operation, e.g.,using a lever or other device to move the intermediate section asdesired. Thus, the feeder 400 can be controlled manually to shutoffflow, to deliver maximum flow or to deliver material at any intermediateflow rate. Optionally, such a manual implementation could be achievedwithout requiring a source of power or any control circuit.

In other implementations, the feeder 400 can be implemented with asystem having at least some automated control of feeding. For example,the member 420 or other device could be configured for control by acontrol circuit and one or more servo motors to control the angle of themember 420, which could optionally be varied during a feeding cycle.

In the described feeder implementations, only the segments of the bodyand structures attached to it (such as a motor or a member) move duringoperation, so there are no internal moving parts. In the illustratedimplementations, the feeders typically eliminate at least one valve,which is one specific component having internal moving parts. As aresult, the feeders tend to be less costly to produce and maintain andmore reliable than conventional feeding technologies having internalparts. Many internal parts are subject to fouling during operation andare prone to wear faster, particularly in applications where feeding ofgranular polysilicon material is involved. Maintenance or repair of suchinternal parts requires considerable downtime.

In the described feeder, there are fewer components and fewer differentmaterials that contact the material being fed than in conventionalfeeders. As a result, there is a much lower risk of contamination to thematerial being fed. In some implementations of the feeder used forfeeding high purity granular polysilicon, the body 102 is made of asingle length of polyurethane hose that poses little contamination risk.

As stated, at least the displaceable body segment 108, or the entirebody 102, can be configured to be flexible so that it can be resilientlydeformed or distorted, e.g., through the positions shown in FIGS. 2-13and the trajectory P of FIG. 14. In some implementations, the body ismade of a section of flexible hose, such as a hose made of polyurethanematerial having sufficient thickness to withstand selected operatingrequirements. Suitable polyurethane hose suppliers include, e.g.,Kuriyama of America, Inc. (see, e.g., Tigerflex Model VOLT200 athttp://products.kuriyama.com/category/tigerflex-thermoplastic-industrial-hoses),Masterduct Inc. (https://www.masterduct.com/material-handling-hoses),Hosecraft USA(https://www.hosecraftusa.com/application/Material_Handling_Hoses) andNorres Schlauchtechnik GmbH(http://www.norres.com/us/products/industrial-hoses-technical-hoses/).It is of course possible to use other materials (such as, e.g., EPDMrubber, Styrene-butadiene rubber, natural rubber, other elastomericmaterials, other resilient materials, etc.) to achieve the desiredflexibility of the displaceable body segment 108. In addition, it wouldbe possible to configure the body to have multiple segments of differentmaterials and/or to have multiple layers. Further, in someimplementations, it may be desirable to include a bellows section alonga section of the displaceable body segment. As stated, contact metalcontamination of the material being fed can be reduced by usingcomponents and/or coatings made of selected materials, includingpolyurethane.

FIGS. 17 and 18 are schematic illustrations of an alternativeimplementation in which a double acting pneumatic cylinder 230 or otherlinear actuator is used to impart the desired motion to the displaceablebody segment 108 or body 102 instead of the motor 130. As shown in FIG.17, the movable end of the cylinder 230 is connected to the displaceablebody segment, and the opposite stationary end is connected to a fixedlocation. The cylinder 230 would also be supplied by suitable fluidsource to move back and forth and to pivot to achieve the desired motion(such as is shown schematically in FIG. 18) and corresponding desiredfeed rate. Of course, mechanisms other than the motor 130 and thecylinder 230 could be used to move the displaceable body segment.

FIG. 22 is a schematic illustration of another alternativeimplementation in which a source of vacuum or suction force is used inthe area near the outlet 307 of the feeder to help control dust that mayarise during feeding operations. In some situations, e.g., if materialis being fed from a higher fall height, a dust cloud can form from thefalling material impacting a surface and/or previously fed material. Toaddress this situation, which is usually undesirable, a suction hood 300can be positioned to at least partially surround the outlet 307. Thesuction hood 300 can be connected via a flexible supply line 302 to avacuum or suction source 304. In use, a vacuum or suction force at thesuction hood 300 is set to be sufficient to assist in withdrawing dustinto the hood 300, but without adversely affecting the feeding ofmaterial in a substantially opposite direction through the outlet 307.

In the illustrated implementation, the suction hood 300 is positionedrecessed from the outlet 307 by a selected distance R, which also helpsadjust the effect of the suction force to prevent it from adverselyaffect the feeding of material. In some implementations, the suctionhood 300 is recessed from the end of the outlet by about 0.5 inch.

In view of the many possible embodiments to which the disclosedprinciples may be applied, it should be recognized that the illustratedembodiments are only preferred examples and should not be taken aslimiting in scope. Rather, the scope is defined by the following claims.I therefore claim all that comes within the scope and spirit of theseclaims.

1. A feeder operable to convey a divided solids material, comprising: aconduit having a hollow body with a length, a first end, a second endopposite the first end and a displaceable body segment defined along atleast a portion of the length; the displaceable body segment having atleast a first fixable location positionable at a first fixed location;an actuator positioned to apply force to the conduit and controllable todisplace the displaceable body segment to cause selected flow of dividedsolids material within the conduit in a feed direction extendinggenerally from the first end to the second end.
 2. The feeder of claim1, wherein the actuator is supported by the conduit and moves with thedisplaceable body segment during a feeding operation.
 3. The feeder ofclaim 2, wherein the actuator comprises a rotating offset mass, andwherein the rotating offset mass is operated to generate oscillatingmotion of the displaceable body segment and the attached actuator. 4.The feeder of claim 2, wherein the displaceable body segment iscyclically displaced through a closed trajectory having at least one ofa vertical component and a horizontal component.
 5. The feeder of claim2, wherein the displaceable body segment has a second fixable locationdownstream of the first fixable location in the feeding direction andpositionable at a second fixed location.
 6. The feeder of claim 1,wherein the displaceable body segment has a curved profile, wherein thecurved profile has a length longer than a shortest distance separatingthe first fixable location and a second fixable location, and whereinthe actuator is attached to the displaceable body segment approximatelyat an inflection point for a curve of the curved profile.
 7. The feederof claim 1, wherein the actuator is positioned stationarily and has acontrollably movable element that contacts the displaceable bodysegment.
 8. (canceled)
 9. The feeder of claim 1, Wherein the actuator isan elongate member having a distal end pivotable into contact with thedisplaceable body segment to selectively move the displaceable bodysegment and a proximal end pivotably connected to a pivot point.
 10. Thefeeder of claim 1, wherein the displaceable body segment comprises anintermediate section configured to collect a portion of the dividedsolids material when the displaceable body segment is at rest.
 11. Thefeeder of claim 10, wherein the intermediate section is configured tocollect a leading edge of a flow of divided solids material receivedfrom the first end of the feeder.
 12. The feeder of claim 1, wherein thedisplaceable body segment comprises an intermediate section configuredfor positioning at a slight angle relative to horizontal, a firstupright section positioned upstream of the intermediate section and asecond upright section positioned downstream of the intermediatesection.
 13. (canceled)
 14. (canceled)
 15. A feeder, comprising: aconduit having an inlet end, an outlet end opposite the inlet end and adisplaceable body segment defined along a feeding direction between theinlet end and the outlet end; the inlet end being configured forconnection to a source of material to be fed by the feeder; the outletend being configured to convey divided solids material from the feederto a location downstream of the feeder, wherein the outlet end isconfigured for positioning at a lower height than the inlet end; thedisplaceable body segment being sized to have a length longer than ashortest distance between the inlet end and the outlet end and to definea curved profile with at least one inflection point when installed; thedisplaceable body segment when installed defining an intermediatesection configured to support accumulated divided solids materialtherein at an angle of repose of the material, and to reduce movement ofmaterial in the feeding direction when the displaceable body segment isat rest; and an actuator connected to the displaceable body segment tocontrollably displace the displaceable body segment during a feedingoperation.
 16. (canceled)
 17. (canceled)
 18. (canceled)
 19. The feederof claim 15, wherein the intermediate section is caused to be displacedfrom a substantially lateral position at which no flow occurs to adownwardly tilted position at which flow towards the outlet end occurs.20. The feeder of claim 15, wherein the actuator is configured to moveat a rate sufficient to cause displacement of the displaceable bodysection such that the solids material moves at a selected rate between alow trickle flow and a high bulk filling flow.
 21. A method of conveyinga divided solids material with a feeder, comprising: using a sensor tomonitor an amount of the divided solids material being conveyed with thefeeder; receiving signals from the sensor at a controller; sendingcontrol signals from the controller to the feeder to control a flow rateof the divided solids material over a flow rate range ratio of greaterthan 1:50 of a low flow rate to a high flow rate.
 22. The method ofclaim 21, wherein using a sensor to monitor an amount of the solidmaterial being conveyed comprises configuring the sensor to measure aloss of weight of the solid material from a source of the materialpositioned upstream of the feeder.
 23. The method of claim 21, whereinusing a sensor to monitor an amount of the solid material being conveyedcomprises configuring the sensor to measure a gain in weight from thesolid material conveyed to a receptacle positioned downstream of thefeeder.
 24. The method of claim 21, wherein the feeder comprises aconduit segment for receiving the solid material and that isdisplaceable according to the control signals from the controller toachieve a desired flow rate of the material from the feeder.
 25. Themethod of claim 21, wherein the flow rate range ratio is greater than1:4000.
 26. A method of conveying divided polysilicon, comprising:receiving divided polysilicon from a source into a conduit of a feeder;controllably moving the conduit through an operation path in which theconduit is positioned in at least a first position at which flow throughthe conduit occurs and a second position at which flow through theconduit is stopped; and receiving the divided silicon material flowingthrough the conduit, when the conduit is positioned at least in a firstposition, in a receptacle positioned downstream of an outlet end of theconduit.